Publix is the place to go, call ahead and talk with someone also go on-line and check out the decorated cakes, even if there isn't a unicorn per say shown, give them a call and they will so everything possible to make it happen. There is one at 7880 Winter Garden Vineland RD, which is sorta out the back gates of WDW, and I know that they do a great job. That's were I shop as I am a local. From POR or POFQ is about a 10 minute drive.